I have a Dublin to HKG booking on BA J/A outbound December 2022 return January 2023 booked through a third party online website. I had input CX membership number as I have no status with BAEC and wish to book seats 7 days prior to departure.
I realised my "CX collection period" for renewal purpose does not start till Januray 2023. Is it possible to change the outbound membership details to BAEC after getting seats allocated (say, few days before check in) and earn Avios on the outbound. Will the system delete my seat choice? Will I be able to change back membership details to CX for return flight in January 2023 to clock CX points?
Since details are originally submitted through third party, they cannot be changed through MMB on BA website, but can be done through Customer Service or chat. CX told me they normally expect the entire itinerary to be credited to same program.
Thank you for your advice!